Gas turbine engines for use in commercial aircraft include a compressor portion that compresses air and provides the compressed air to a combustor portion along a primary fluid flowpath. The combustor receives fuel from an aircraft fuel system and ignites a mixture of fuel and compressed air. The combustion gasses resultant from the combustion are passed through a turbine portion of the gas turbine engine, and drive the stages within the turbine portion to rotate. Each of the stages is connected to a shaft, and rotation of the turbine stages in turn drives rotation of the shaft.
The turbine portion is divided into at least two sequential turbine sections, with combustion gasses flowing through the second turbine section being at a lower pressure than combustion gasses flowing through the first turbine section. The first turbine section is connected to a first shaft and drives at least a high pressure section of the compressor portion. The second turbine section is connected to a second shaft and drives at least a low pressure section of the compressor portion. The second shaft is positioned radially inward of the first shaft.
In order to structurally support each shaft relative to the other shaft, support the rotor system, and support an engine case relative to each of the shafts, multiple structural supports and bearings are located in the gas turbine engine and provide support.